1. What defines an ampere? (Cong Feng) Ans: In practical terms, the ampere is a measure of the amount of electric charge passing a point in an electric circuit per unit time with 6.241 × 1018 electrons, or one coulomb per second constituting one ampere.
Reference: http://en.wikipedia.org/wiki/Ampere
2. What exactly is an electric current? (Eric)
Ans: An electric current is a flow of electric charge through a medium. This charge is typically carried by moving electrons in a conductor. It can also be carried by ions in an electrolyte, or by both ions and electrons in a plasma.
Reference: http://en.wikipedia.org/wiki/Electric_current
3.How do electrons in an electric current move? (Jaron)
Ans: If the two requirements of an electric current are met (having a Closed Conducting Path and an Energy Supply), then charge will flow through the external circuit. The particles that carry charge through wires in a circuit are electrons, and these negatively charged electrons move in the direction opposite of the electric field. However, the direction of electrons in an electric current, by convention, is the direction in which a positive charge would move, as Ben Franklin had envisioned positive charges as the carries of charge, and the convention has stuck still today. Thus, the current in the external circuit is directed away from the positive terminal and towards the negative terminal of the battery.
Reference: http://www.physicsclassroom.com/class/circuits/u9l2c.cfm
Ans: In practical terms, the ampere is a measure of the amount of electric charge passing a point in an electric circuit per unit time with 6.241 × 1018 electrons, or one coulomb per second constituting one ampere.
Reference:
http://en.wikipedia.org/wiki/Ampere
2. What exactly is an electric current? (Eric)
Ans: An electric current is a flow of electric charge through a medium. This charge is typically carried by moving electrons in a conductor. It can also be carried by ions in an electrolyte, or by both ions and electrons in a plasma.
Reference:
http://en.wikipedia.org/wiki/Electric_current
3.How do electrons in an electric current move? (Jaron)
Ans: If the two requirements of an electric current are met (having a Closed Conducting Path and an Energy Supply), then charge will flow through the external circuit. The particles that carry charge through wires in a circuit are electrons, and these negatively charged electrons move in the direction opposite of the electric field. However, the direction of electrons in an electric current, by convention, is the direction in which a positive charge would move, as Ben Franklin had envisioned positive charges as the carries of charge, and the convention has stuck still today. Thus, the current in the external circuit is directed away from the positive terminal and towards the negative terminal of the battery.
Reference:
http://www.physicsclassroom.com/class/circuits/u9l2c.cfm
4.How did the word "ampere" originate? (Colman :D:D:D:D)
Ans: It was named after André-Marie Ampère, one of the forefathers of electromagnetism. He invented many things such as
the astatic needle, a critical component of the modern astatis galvanometer. He was also the first to demonstrate that a magnetic field is generated when two parallel wires are charged with electricity.
References :
http://wiki.answers.com/Q/What_is_the_Origin_of_word_ampere#ixzz1Qki7qVyH
http://www.rare-earth-magnets.com/t-andre-marie-ampere.aspx
5. How do you measure Electric Current? (Kuang Ning)
Ans:
Using Ohm's law, which states that electric Current equals voltage over resistance, we can find out current in amperes. For, example, for a case of 18 volts and 3 ohms of resistance, it is as follows:
References:
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmlaw.html
http://www.allaboutcircuits.com/vol_1/chpt_2/4.html